I am having what appears to be the same problem as several other people with this setup. I haven't seen anyone find the answer yet though. I am able to receive e-mail with no problem, but I am getting some SASL authentication errors when I try to send e-mail out. The follwing is in the mail.log file when I try to send e-mail:

I am at a real loss here. All of the configs appear to be correct. Obviously the database itself works since the checking mail works fine. I did spot check things with PhpMyAdmin though and everything looks correct. Any thoughts on what could be wrong here?